docs: def consume(self, service_agreement_id, did, service_definition_id, consumer_account,
                  destination, index=None):
          """
          Consume the asset data.
  
          Using the service endpoint defined in the ddo's service pointed to by service_definition_id.
          Consumer's permissions is checked implicitly by the secret-store during decryption
          of the contentUrls.
          The service endpoint is expected to also verify the consumer's permissions to consume this
          asset.
          This method downloads and saves the asset datafiles to disk.
  
          :param service_agreement_id: str
          :param did: DID, str
          :param service_definition_id: identifier of the service inside the asset DDO, str
          :param consumer_account: Account instance of the consumer
          :param destination: str path
          :param index: Index of the document that is going to be downloaded, int
          :return: str path to saved files
          """
          ddo = self.resolve(did)
          if index is not None:
              assert isinstance(index, int), logger.error('index has to be an integer.')
              assert index >= 0, logger.error('index has to be 0 or a positive integer.')
          return self._asset_consumer.download(
              service_agreement_id,
              service_definition_id,
              ddo,
              consumer_account,
              destination,
              BrizoProvider.get_brizo(),
              self._get_secret_store(consumer_account),
              index
          )